iStockphoto/Thinkstock(PHILADELPHIA) -- Philadelphia police are investigating an early morning shooting that took the life of a Temple University Hospital employee.

Detectives said an armed 25-year-old security guard double-parked to pick up his sister on Sunday in a West Philadelphia neighborhood. Another car being driven by a man police identified as hospital worker Mark Ellis parked behind the car driven by the unidentified security guard to drop off his fiancée, Syreeta Manire.

Ellis, 25, was unable to get around the car of the security guard, which lead to the argument after he dropped off Manire, his family told ABC News affiliate WPVI-TV.

The security guard was upset with Ellis when he started to drive too close to him, Manire’s sister Mercedes Echols told WPVI.

“The guy gets out and says, ‘Don’t be pulling up on my car that way,’” Echols told WPVI.

She said Ellis replied, “Go park your car, move your car.”

Both men were armed and it’s unclear who pulled a gun out first during the dispute. But both men fired shots and Ellis was struck in the chest and killed, police said.

The Philadelphia police were still investigating the case and so far have not brought any charges against the security guard, who was taken in for questioning. The guard’s name was not released by police.